Against Mrs. Medlock's orders, Mary finds the cause of the wailings that she hears. She finds Mr. Craven's son, Colin. He has been shut up in his room for most of his life because of his father's emotional state and the worry that he is a hunchback, and will die.
I'm not a cripple, I'm not!
Secretly, Mary sees Colin to help him have less emotional breakdowns. She eventually invites Dickon to come with her and give Colin his first taste of spring.
I'm going to live for ever and ever!
Colin goes to the secret garden with Mary and Dickon. In one of their many visits to the garden, they meet Ben Weatherstaff. He confesses that he has made annual visits to the garden after Mrs. Craven's passing.
Ben accuses Colin of being a cripple, but Colin denies it. He forces himself to stand, and Mary and Dickon considers this as a form of magic from the garden.
When Dickon's mother hears of this news, she writes to Mr. Craven, and tells him to come home immediately. He has a dream of his late wife calling him in the garden, he gets up and returns home. Mr. Craven finds his son in the garden, healed.